The IRS has discovered more than 1 million Americans whose Social Security numbers were stolen by illegal immigrants, but officials never bothered to tell the taxpayers themselves, the agency’s inspector general said in a withering new report released Tuesday.

Investigators first alerted the IRS to the problem five years ago, but it’s still not fixed, the inspector general said, and a pilot program meant to test a solution was canceled — and fell woefully short anyway.

As a result, most taxpayers don’t learn that their identities have been stolen and their Social Security files may be screwed up.

“Taxpayers identified as victims of employment-related identity theft are not notified,” the inspector general said.

The report alarmed lawmakers on Capitol Hill, who were shocked that the IRS had gone for so long without fixing the issue.